Uh, yeah you can. If both parties are in agreement you can absolutely null a contract. I'm not sure how the NFL works but I'd be willing to bet negotiating a new contract renders the old one null and void following some mandatory procedure or filing or something. Maybe you meant Dallas couldn't do it just on their behalf, in which case if Ware refuses to negotiate a new contract he's more than likely going to be hitting the street and may make 50% of his current base salary, so it'd be in his best interest to negotiate. And what bkight said, regardless we're still responsible for the 8.5m.